Evaluation of the coupled effect of strain localization and asymmetric damage distribution on rope response: numerical approach based on a nonlinear cable-beam element

Abstract

In this paper, a numerical model to evaluate the impact of the presence of fractured rope components on the static response of ropes is presented. Specifically, the proposed model couples the effects of two phenomena that rule damaged rope response: strain localization and asymmetry in damage distribution. The proposed model relies on the nonlinear finite element method in which the damaged rope is discretized along its length into 3D uniaxial two-noded nonlinear cable-beam elements with Bernoulli's kinematic hypothesis. These elements account for the helical structure of a rope (cable) as well as the axial-bending, axial-torsional, and bending-torsional interactions. Experimental static tensile test data reported in the literature of homogeneous polyester ropes with overall diameters that range from 32 mm to 166 mm are used to validate the proposed model. Tested ropes are asymmetrically damaged on the surface of the rope cross-sections in which initial damage levels (percentage of the broken components of the damaged cross-section with respect to the intact rope) vary from 5% to 15%. Comparison results indicate that the proposed model accurate predicts the static response of damaged ropes, considering a wide range of rope diameter and damage level values, achieving numerical robustness and computational efficiency.